1. Technical Field
The present invention relates to an image capturing apparatus that captures an image, an image capturing method, and a computer readable medium storing thereon a program. In particular, the present invention relates to an image capturing apparatus, an image capturing method, and a computer readable medium storing thereon a program for identifying the depth of an object inside a subject.
2. Related Art
A technique is known for viewing organic information near a surface of a living organism by controlling the wavelength region of light irradiating a subject, as disclosed, for example, in Japanese Patent Application Publications No. 2002-95635, No. 2002-34893, and No. 2002-34908.
Furthermore, a technique is known for detecting a lesion in an organism based on a fluorescent light component in a short wavelength region and a fluorescent light component in a long wavelength region extracted from an autofluorescent component emitted by the organism, as in, for example, Japanese Patent Application Publication No. 10-225436. Furthermore, a technique for generating an image indicating an oxidized hemoglobin distribution by calculating a difference between two images resulting from different wavelength regions is known as in, for example, Japanese Patent Application Publications No. 2002-272744 and No. 2006-326153.
The above techniques, however, cannot measure the depth of a blood vessel from the surface of the organism. For example, when using a technique that measures the depth of the blood vessel based on the amount of light reflected from the organism, this measurement is affected by the texture of the surface of the organism and changes in the amount of light due to movement of the light source or the like, so that a stable measurement result cannot be obtained.